Circadian Rhythms of C‐FOS Expression in the Suprachiasmatic Nuclei of the Common Vole (Microtus arvalis)

Abstract

The suprachiasmatic nuclei of the hypothalamus (SCN) are the master circadian clock in mammals. Transcriptional activity in this master clock has a marker in the immediate-early gene c-Fos. Within the SCN, distinct differences in c-Fos in the ventrolateral and the dorsomedial SCN have been reported for rodent species such as rats, mice and hamsters.We studied C-FOS expression in the Common vole (Microtus arvalis) SCN under LD 12:12h and under constant dim light conditions. In the vole dorsomedial SCN rhythmic C-FOS expression was seen in LD with a clear peak in the middle of the light period. Under constant dim light conditions we report constitutive, non-rhythmic expression of C-FOS in the dorsomedial SCN. This pattern is consistent with circadian organization of behavioral activity, which is weak in voles, and may be lost under constant dim light conditions. In the ventrolateral SCN, under LD conditions we observed a rise in C-FOS expression prior to lights-on followed by peak expression at lights-on. Another peak was seen at lights-off. In an additional experiment we subjected animals to LD 16:8 to test the hypothesis that the dawn and dusk peaks in ventrolateral C-FOS expression change phase along with the photoperiod.

Co‐expression of diurnal and ultradian rhythms in the plasma metabolome of common voles (Microtus arvalis)

“…Ultradian rhythms are observed in processes such as locomotor activity and feeding behavior, including in rodent species in which the circadian clock has been perturbed. [6][7][8][9][10][11][12] These cycles are also seen during non-Rapid-Eye-Movement (REM) and REM sleep alternations, 13 in circulating glucocorticoid levels, 14 central monoamine release, 15 and gene expression that is enriched for metabolic processing. 16,17 These ultradian rhythms have long been hypothesized to maintain metabolic homeostasis, [18][19][20] and intrinsically driven ultradian rhythms have indeed been observed in various aspects of cellular metabolism that also express circadian rhythms, such as cell mass, ATP concentration, protein synthesis, and respiration in vitro.…”

“…While understanding mechanisms that drive perturbed circadian metabolic rhythms is deemed paramount by researchers, health professionals, pharmaceutical industry, and funders alike, it is often overlooked that the same metabolic processes also co‐express rapid, <24 h (ultradian) rhythms. Ultradian rhythms are observed in processes such as locomotor activity and feeding behavior, including in rodent species in which the circadian clock has been perturbed 6–12 . These cycles are also seen during non‐Rapid‐Eye‐Movement (REM) and REM sleep alternations, 13 in circulating glucocorticoid levels, 14 central monoamine release, 15 and gene expression that is enriched for metabolic processing 16,17 .…”

Identification of Photoperiod-Induced LncRNAs and mRNAs in Pituitary Pars Tuberalis of Sheep

“…The role of FOS and SOCS3 in SCN has been reported in long-day breeding animals (redheaded bunting, rat, and hamster), which are enriched in the TNF signaling pathway and circadian entrainment. Their expression patterns under SP and LP are opposite to those of short-day breeding animals (41)(42)(43). For example, FOS is predominantly expressed in the SCN of redheaded buntings under LP conditions (42).…”